textproduct: Albany

SYNOPSIS

Blustery and chilly today with lingering lake effect snow showers in the western Adirondacks and Mohawk Valley. Snow showers return tomorrow mainly near and north of I-90 before a clipper disturbance developing off the mid-Atlantic coast grazes areas mainly south of I-90 with a period snow tomorrow night into Sunday. Then, colder and blustery conditions return Sunday into Monday.

SHORT TERM /THROUGH SUNDAY/

Key Messages:

- High confidence in below normal temperatures continuing through early next week.

- A clipper will bring light snow to areas mainly south of I-90 Saturday into early Sunday morning. There is a 40-50% chance of at least 2" of snow for the central and southern Taconics, Litchfield and Berkshire County, into parts of the mid-Hudson Valley.

Discussion:

Windy and chilly this afternoon with the ASOS and NYS mesonet observations showing gusts up to 30 to 35mph and with temperatures in the mid 20s to low 30s, it feels more like mid teens to mid-20s. Continued westerly flow have maintained light lake effect snow showers tracking down the Mohawk Valley into parts of the Capital District today but with inversion heights only around 800hPa, snow shower intensity has remained light. As we approach sunset, shortwave ridging builds into the Northeast allowing winds to relax and helping to improve the "feel-like" temperatures. The incoming ridge will also send the lake effect snow showers northward into the western Adirondacks and allow them to weaken. Overall, only expecting coatings to 1 inch through tonight and with partial clearing tonight, expecting chilly overnight lows dropping into the teens.

Tomorrow starts off dry but then as the ridge axis shifts to our east, a period of warm air and moisture advection ensues. While skies will trend cloud across the region, guidance continues to suggest the best forcing is positioned mainly north of I-90 where we have widespread chance POPs for scattered snow showers starting 15 - 18 UTC and continuing into the afternoon. The south facing slopes of the southern Adirondacks into the southern Greens have the highest chance for snow showers but given the overall weak forcing/moisture, total snow accumulations is again limited to coating to 1 inch. Otherwise, southerly winds and weak warm air advection will help temperatures rise closer to normal with daytime highs reaching into upper 20 to mid-30s.

By Saturday evening, the associated cold front will slides south and eastward through the region with additional areas of snow showers developing along and just ahead of the boundary but again limited moisture and forcing will keep additional snow accumulations light. In the wake of this front, a lake effect band looks to develop off Lake Ontario Saturday night and become directed into northern Herkimer County, mainly north of Route 28. While snowfall rates looks to be 0.5-1" at times, the duration of the lake effect band is short which will keep total snowfall amounts low with the current forecast showing amounts ranging 2 to 4 inches.

As the cold front slides into the mid-Atlantic region, a weak shortwave rounds the base of the closed parent low positioned over the Upper Midwest and as the two phase, the closed low quickly amplifies and digs towards the East Coast as it becomes neutrally tilted. Rapidly falling heights in response to the enhanced positive vorticity advection will allow a sfc low to rapidly develop along the cold front. Additional forcing for ascent from the sfc low's favorable positioning in the equatorward entrance region of a strengthening ~140kt jet will help induce cyclogenesis as the low shifts off the NJ coast early Sunday. While this developing coastal low is positioned well to our south, the northern fringe of its precipitation shield looks to graze the mid-Hudson Valley into the central/southern Taconics, western MA and NW CT. Latest probabilistic guidance shows the 25th and 75th percentile spread in QPF amounts in these areas ranging from a few hundredths up to near two tenths of an inch so there remains a moderate amount of uncertainty in exact snowfall amounts. However, there is only a 20 to 40% chance for QPF amounts to exceed 0.25" so there is increasing confidence for reasonable high-end snowfall amounts to be near 3 inches with the current forecast favoring 0.5 to 2.5 inches. There will be a south to north snowfall gradient with snowfall amounts decreasing heading towards the Capital District where there is only a 25% chance for snowfall amounts to exceed 1 inch. The Winter Weather Severity index continue to highlight only "minor" impacts focused in far southern Dutchess and Litchfield County but given the cold ground temperatures and the fact that snow arrives overnight into early Sunday, snow will easily accumulate on any untreated sfc leading to slippery travel. Snowfall quickly ends from northwest to southeast Sunday morning by 12 - 15 UTC with NW CT likely the last to see snow end. Behind the exiting coastal low Sunday morning, winds turn breezy with strong cold air advection quickly ensuing. Daytime temperatures likely will not rise out of the 20s and with wind gusts up to 25mph, it will feel even chillier in the teens.

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/

Key Message:

- Below normal temperatures persist through Monday before temperatures gradually trend milder mid to late next week.

Discussion:

An impressive ~1040hPa high positioned over the Central CONUS builds eastward early next week and with our departing coastal low off shore, the pressure gradient looks to remain tight Sunday night into Monday. With northwest winds directing a much colder Canadian air mass into the Northeast (850hPa isotherms 2 to 3 standard deviations below normal per the NAEFS), confidence remains high in quite cold Sunday night low temperatures. In fact, there is greater than 75% chance for Sunday night temperatures to drop below 15 degrees. With northwest winds remaining a bit elevated, we will keep an eye on wind chill values but as of snow, there is low confidence in needing cold weather advisories. The arctic air mass persists into Monday with less than 20% chance for daytime highs to exceed 25 degrees for much of eastern NY and western New England. Luckily, the wind finally diminishes as shortwave ridging builds overhead.

Weak warm air advection returns Monday night into Tuesday as a another clipper passes well to our north and west leading to increasing chances for snow showers but lackluster moisture will keep amounts low. A warming trend finally ensues for the middle and end of the week as a deepening low pressure system passes to our west across Central Canada inducing southwest flow across the eastern CONUS. Latest probabilistic guidance shows greater than 75% chance for temperatures across the region to exceed 40 degrees on Thursday. Chances for precipitation increase heading into Friday as the main potent cold front pushes through and given the mild air mass ahead of it, there is increasing confidence that p-type will be mainly rain, at least to start. However, we will closely monitor thermal profiles and any potential p-type challenges depending on how the inland track low tracks.

AVIATION /20Z FRIDAY THROUGH WEDNESDAY/

Predominate VFR conditions expected through the end of the TAF period. PSF will be remain low end VFR through 04 UTC tonight and while there may be brief periods of MVFR, not enough confidence to include in the latest TAF update. Otherwise, clouds lower tomorrow morning as a warm front approaches with potential for light snow showers to develop mainly over GFL and PSF where we included a PROB30 group for MVFR conditions starting 15 - 18 UTC. Less confident at ALB so only show VCSH there and POU should remain well south of any snow showers.

Gusty westerly winds through 21-22 UTC today at ALB, PSF and GFL with sustained winds 10-20kts and gusts up to 25-30mph. Winds turn light and variable tonight before becoming southerly by 14-15 UTC with sustained winds reaching 5-8kts and gusts up to 15-20kts.

Outlook...

Saturday Night: Moderate Operational Impact. Chance of SN. Sunday: No Operational Impact. NO SIG WX. Sunday Night: No Operational Impact. NO SIG WX. Monday: No Operational Impact. NO SIG WX. Monday Night: Moderate Operational Impact. Chance of SN. Tuesday: No Operational Impact. NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: No Operational Impact. NO SIG WX.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.